[PATCH 3.10 123/180] iio: Fix error handling in iio_trigger_attach_poll_func

[Willy Tarreau]

From: Crestez Dan Leonard <leonard.cres...@intel.com>

commit 99543823357966ac938d9a310947e731b67338e6 upstream.

When attaching a pollfunc iio_trigger_attach_poll_func will allocate a
virtual irq and call the driver's set_trigger_state function. Fix error
handling to undo previous steps if any fails.

In particular this fixes handling errors from a driver's
set_trigger_state function. When using triggered buffers a failure to
enable the trigger used to make the buffer unusable.

Signed-off-by: Crestez Dan Leonard <leonard.cres...@intel.com>
Cc: <sta...@vger.kernel.org>
Signed-off-by: Jonathan Cameron <ji...@kernel.org>
Signed-off-by: Willy Tarreau <w...@1wt.eu>
---
 drivers/iio/industrialio-trigger.c | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/industrialio-trigger.c 
b/drivers/iio/industrialio-trigger.c
index 4d6c7d8..301becc 100644
--- a/drivers/iio/industrialio-trigger.c
+++ b/drivers/iio/industrialio-trigger.c
@@ -203,22 +203,35 @@ static int iio_trigger_attach_poll_func(struct 
iio_trigger *trig,
 
        /* Prevent the module from being removed whilst attached to a trigger */
        __module_get(pf->indio_dev->info->driver_module);
+
+       /* Get irq number */
        pf->irq = iio_trigger_get_irq(trig);
+       if (pf->irq < 0)
+               goto out_put_module;
+
+       /* Request irq */
        ret = request_threaded_irq(pf->irq, pf->h, pf->thread,
                                   pf->type, pf->name,
                                   pf);
-       if (ret < 0) {
-               module_put(pf->indio_dev->info->driver_module);
-               return ret;
-       }
+       if (ret < 0)
+               goto out_put_irq;
 
+       /* Enable trigger in driver */
        if (trig->ops && trig->ops->set_trigger_state && notinuse) {
                ret = trig->ops->set_trigger_state(trig, true);
                if (ret < 0)
-                       module_put(pf->indio_dev->info->driver_module);
+                       goto out_free_irq;
        }
 
        return ret;
+
+out_free_irq:
+       free_irq(pf->irq, pf);
+out_put_irq:
+       iio_trigger_put_irq(trig, pf->irq);
+out_put_module:
+       module_put(pf->indio_dev->info->driver_module);
+       return ret;
 }
 
 static int iio_trigger_detach_poll_func(struct iio_trigger *trig,
-- 
2.8.0.rc2.1.gbe9624a